Ng'iresi is one of several villages in the general Arusha area that offer tourists the possibility of experiencing something of local life beyond the usual safari attractions. It's a good option, since most visitors are unlikely to just drive into a local village, start walking around, and really experience daily life. In Ng'iresi, people expect and welcome tourists, and generally go about their normal activities. So don't expect any staged Maasai warrior dances.
The reason village residents welcome tourists is that part of the tour fees go towards supporting their primary school. The head of the village, Mzee Loti, will tell you this story as you are offered tea and coffee in his home. It's a modestly furnished home by western standards, but the best in the village and contains a Sony television. There's the opportunity to make an additional donation to the village and to buy souvenirs made by the local women. As we realized later during our trip, the prices were quite reasonable and there was no sales pressure.
(NOTE: "Mzee" is a Swahili title of respect for old, and presumably wise, men. I can't think of an English equivalent. It's about ten levels above "old geezer".)
We had a guide to show us through the village, a tour that took about two hours. For the first half of the tour, we were followed by a boy who was probably 4 or 5 years old. I wondered if a child that young could roam so freely in any of our "developed" countries.
We started by heading down the road we had driven in on, with our guide pointing out plants, cultivation methods, and explaining the size of the fields and their boundaries. Along the way, we spotted the biggest (maybe the only) chameleon I've ever seen. (See picture.) We eventually reached the school and went inside the local church. Our return was on local footpaths and included a visit to a family compound, including a mud-walled rondeval. We entered and saw the cooking fire in the middle and the 3-foot mud wall that separates the human inhabitants from the cattle at night. Soon we were back at Mzee Loti's house.
If you want to visit Ng'iresi or experience a similar cultural program, ask to travel agent or tour operator to include it in your schedule when you are in the Arusha area. We took a half-day tour, but full-day tours that include more hiking on the slopes of Mt. Meru, are also offered